New surveillance video released this afternoon from a Metro Lift bus shows the the 65-year-old doctor riding a yellow bike to work and the suspect trailing closely behind him.

The bus was traveling on Main Street near West Holcombe Street, in the opposite direction of Dr. Hausknecht and the suspected gunman, shortly after 8:45 a.m. Friday.

A block away, just moments later, the shooter shoots and kills Dr. Hausknect, then cycles away west on Southgate Blvd. towards Travis Street.

Houston police also released a clearer image of the suspect with this surveillance photo.

The suspect is described as a white or Hispanic male, around 30 years old. He was last seen on Friday wearing a blue, short-sleeved polo shirt, a khaki ball cap, khaki shorts, and carrying a large, fully-loaded olive green backpack.

Dr. Alpesh Shah worked with Dr. Hausknect for nearly 20 years. The fellow interventional cardiologist described his colleague as a quiet, reserved gentlemen who was precise in his work and an irreplaceable professional in his field.

"In our Houston Methodist community, Mark Hausknecht represents so much to all of us that news traveled very fast. It became quite solemn and we realized what a loss it's been for all of us. Texas Medical Center is such a safe place. This is not a place we associate with crime or danger," Dr. Shah said.

Dr. Shah said the hospital is now working on a plan to get Dr. Hausknecht's patients taken care of with an alternate doctor.

Dr. Hausknecht’s family has asked for privacy during this difficult time but said they are in the process of making funeral arrangements.

Authorities are now offering up to a $5,000 reward for any information that could lead to an arrest of the suspect. Anyone who knows anything about this man should call Crime Stoppers at 713-222-TIPS.